Rare butterfly is likely
extinct, while imperiled gnatcatcher loses a chunk of
habitat

The fires that blackened 775,000 acres and 2,400
homes in Southern California this October also devastated plant and
animal populations in San Diego County, one of the most
biologically diverse places in the United States, and home of the
country’s first multiple-species habitat conservation plan
(HCN, 11/10/03: San Diego's Habitat Triage).

No other
species has been left in as precarious a position as the
Thorne’s hairstreak, a tiny butterfly that is brownish in
color until the sun gives it a purplish-green iridescence. It was
only discovered by scientists in 1972, and it lives only on
3,500-foot Otay Mountain on the U.S.-Mexican border. The
butterfly’s population has varied yearly, but stood at a few
hundred at most before the fires.

On Oct. 31, a few days
after the fires peaked, biologist Michael Klein saw firsthand the
consequences for the Thorne’s hairstreak. Venturing up the
north side of Otay Mountain, about 15 miles southeast of downtown
San Diego, he came across a series of blackened hills. The Tecate
cypress trees, which host the butterfly and grow in only two other
places in Southern California and northern Baja California, had
been reduced to stumps, he says.

“There
may be an isolated area that survived, but all the known locations
in the entire world where we had reported the butterfly, all six
locations on Otay Mountain, all burned,” says Klein, who runs
a biological consulting firm that surveys wildlife for land
developers. Even if the cypresses regenerate quickly, the
butterfly’s caterpillars generally won’t start eating
them until they are 25 to 30 years old. “(The butterfly) is
one that has potential to go extinct. It’s a high
probability,” says Klein.

“Emotionally,
it’s distressing,” he adds. “It’s not one
of those species that in my lifetime I ever expected to see it
potentially go extinct.”

Scientists probably
won’t be able to draw firm conclusions about the fires’
effects on the butterflies and other wildlife until next spring at
the earliest, says Jane Hendron, a U.S. Fish and Wildlife Service
spokesperson.

But preliminary findings show that two other
butterfly species, the Hermes copper and the endangered Quino
checkerspot, were also seriously damaged. It’s likely that
thousands of butterflies were destroyed. The fires also torched
much of the coastal sage scrub that plays host to the threatened
California gnatcatcher, the poster child for the 1997 Multiple
Species Conservation Program (MSCP).

As the smoke clears,
environmentalists say the fires have confirmed their doubts about
whether the program protected enough land to accomplish its goal to
save 85 imperiled animal and plant species in the midst of Southern
California’s runaway urban sprawl.

Gnatcatcher could be in trouble

Early reports
portray the fire as an equal-opportunity destroyer across San Diego
County. Overall, it burned about 390,000 acres in the county
— nearly 15 percent of the county’s total land area
— according to a mid-November report from a team of
scientists investigating the damages. “The state has never
seen a loss of this magnitude,” the report says.

The
report found that the fire damaged 13 complexes of vernal pools
— small, seasonal wetlands that fill with water during and
after the winter rainy season and play host to as many as seven
federally protected plant and animal species.

Many of the
region’s plants and animals have co-evolved with fire and are
adapted to it, sometimes recovering swiftly in the months and years
after the headlines die down. But historically, fires occurred far
less often than they do now. A century of fire suppression, years
of drought and other factors have turned San Diego’s forests
into tinderboxes, says the service’s Hendron.

The
Tecate cypress, for instance, can survive fires every 40 years. But
fires are now occurring every 20 years, about the time that the
trees reach reproductive age, which raising concerns about how well
the species will recover.

While some patches of green
have already reappeared in the region’s wildlands, those
wildlife species that depend on the recovering vegetation may face
a tough road ahead. Inside the county, the blaze destroyed 71,000
acres, or 30.9 percent of the coastal sage scrub that plays host to
the threatened California gnatcatcher, according to statistics kept
by the nonprofit San Diego Recovery Network, a group consisting of
scientists and environmentalists.

The loss of habitat
— combined with the exotic West Nile virus, which arrived in
the county in fall 2003 (see story page 4) — is expected to
seriously affect the birds next year, according to the
scientists’ report: “The combination of West Nile virus
and reduction in population as a result of the fire may be a major
impact to the California gnatcatcher.”

The report
also says that emergency Endangered Species Act listings may be
warranted for the Hermes copper butterfly, which lost 90 percent of
its habitat, as well as the Thorne’s hairstreak — if
any remain.

Conservation plan called into
question

The fires’ implications for the habitat
conservation plan also remain unclear.

David Hogan of the
Center for Biological Diversity says that because of the fires, his
group is considering asking the Fish and Wildlife Service to
revisit its conclusions from 1997 that the conservation plan
adequately protected the Thorne’s and Hermes butterflies and
the Tecate cypress, and possibly the gnatcatcher.

“The lesson learned from the fires is that the MSCP is too
small and fragmented, and that too much of the preserve can be lost
in one fire event,” says Hogan, whose group has criticized
the conservation plan for many years.

The service’s
Hendron says it’s too early to make such judgments; the true
test will come when the various species of birds and butterflies
enter their breeding seasons and the plants begin to recover. Says
Hendron, “These are all the types of things that are going to
take a little bit of time.”

The author
lives in Tucson, Arizona, where he reports for the Arizona Daily
Star.